HIGH Tc SUPERCONDUCTIVITY: A MODEL BASED ON ANTIFERROMAGNETIC FLUCTUATIONS

The system X–La–Cu–O is described as a Fermi liquid with antiferromagnetic interaction. This interaction gives rise to two types of fluctuations, magnetic and superconducting. As a result, we find a free energy which contains two order parameters which at high temperature give rise to superconductivity and at low temperature to reentry-like paramagnetism. For two-dimensional systems, topological effects give rise to fractional statistics and as a result superconductivity appears when the topological angle θ gives rise to a Bose statistic.